Study of strengthening of an austenitic stainless steel by cold rolling (theoretical and experimental approach)

During deep rolling, high compressive residual stresses are produced on surface of cylindrical parts which may eliminate critical tensile stresses in the surface zone and put the surface zone into compressive stresses. Like shot peening and hammer peening, the effectiveness of this treatment by deep rolling increases the plastic deformation, mechanical properties and fatigue strength of the material. Maximum fatigue strength improvement is generally caused by a substantial plastic deformation of the material and residual stresses generation. Optimum surface treatment depends on many parameters such as applied force, treatment time, shape of the part and roller and type of treated material. To optimize surface treatment parameters, prediction models are currently developed and based on calculation of properties improved by deep rolling technique such as residual stresses . Within the framework of this study, an analytical model for predicting residual stresses produced by deep rolling has been developped. The residual stress results obtained using the modeling approach are validated by measurements carried out using the step by step hole drilling method and X-ray diffraction methods used in CETIM Laboratory.